Sensitization of photographic emulsions with ionic polyalkyene oxide salts



United States Patent SENSITIZATION or PHOTOGRAPHIC EMUL- wrrr-r on c POLYALKYENE oxm Burt I-I. Carroll, Herbert Elins, James L. Graham, and Charles V. Wilson, Rochester, N,Y,,. assignors to Eastman Kodak Company, Rochester, N.Y.,a corporation of New Jersey I .No Drawing. Filed Dec. 10, 1956, Ser. No. 527,13 20 Claims. 01. 96-100) The sensitization of photographic emulsions with various onium, compounds such as cationic surface-active 2,944,900 Patented July 12, 1960 2 a the anionic polyalkylene oxide compounds such as the polyalkylene oxide carboglutamic acid salts, polyalkylene oxide bis-N-carboxymethyl carbamate salts, polyalkylene Oxide bissulfuric acids, etci, A further object is to provide suitable means for reducing any fog accompanying the use of the ionic polyalkylene oxide salt sensitizers.

. Another object is to provide color processes utilizing the emulsions thus sensitized. Other objects will appear from the following description of our invention.

These objects are accomplished in part by the incorporation of the ionic polyalkylene oxide compounds in photographic silver halide emulsions containing coupler quaternary ammonium, phosphonium, and ternary sulfonium salts is known as shown by Carroll U.S. Patent 2,271,623 and Carroll and Allen U.S. Patents 2,275,727 and 2,288,226 as Well as Carroll and Spence US; Patent 2,334,864. The parent invention also shows that emulsions sensitized with the onium compounds can be used in color photography by development of the emulsions with color developing solutions containing coupler compounds which react with color developing agents to form dyes, or the coupler compounds can be present in the emulsions sensitized with the onium compounds.

Similarly, the sensitization of photographic emulsions with various non-ionic polyalkylene oxides such as poly ethylene oxide is shown by U.S. Patents 2,423,549 and 2,441,389..

compounds.

The cationic polyalkylene oxide salts used in'the emulsions are characterized as containing a bivalent polyalkylene oxide radical such as an -(cHioHmHzoHiO)ncniomorncn I corresponding to polyethylene oxide, polypropylene oxide and polybutylene oxide radicals to which is attached at least one onium. salt group such as'a quaternary.

. monium',-*phosphonium" or ternary 'su'lfonium" salt group,

s We have "discovered that when photographic silver halide emulsions adapted particularly for use in color photography, that is, emulsions containing coupler compounds, are sensitized with non-ionic polyalkylene oxide compounds no improvement in sensitivity occurs or else a loss in light sensitivity of the emulsion is sustained,

However, the light-sensitivity of the coupler-containing emulsion is materially increased if instead of using a nonionic polyalkylene oxide sensitizing agent, the emulsion containing the coupler compound is sensitized with an ionic, i.e. a cationic polyalkylene oxide saltsuch as a quaternary ammonium or phosphonium polyalkylene oxide salt or a ternary :sulfonium polyalkylene oxide salt, e.g. tetraethoxyethyl-bis-pyridinium perchlorate, or an anionic polyalkylene oxide compound such as the car:

bamic, glutami-c and sulfuric acid salts below. 'This improvement in light sensitivity appears to be independent of the type of developing agent used for developing the emulsion sensitized with the ionic polyalkylene oxide salt, since the sensitivity increase is obtained with both black-and-white developers and color developers. Little else is known of the mechanism involved, but it has been observed that the effect is independent ,of the type of coupler used in the emulsion since the sensitizing efli'ect is obtained in the presenceof either the phenolic .hy-

droxyl or the reactive methylene types of coupler compounds.

While the mentioned sensitivity increase is obtained when employing the polyalkylene oxide salts in couplercontaining emulsions, this sensitivity increase is sometimes accompanied by increase in general fog, particularly upon storage of the emulsions under adverse conditions of temperature and humidity. Therefore, it may be desirable to employ fog reducing substances in the emulsions as illustrated-in the examples hereinafter.

It is therefore one object of the invention to provide P photographic silver halide emulsions containing coupler compounds which emulsions are sensitized with ionic polyalkylene oxide compounds such as the cationic quaternary ammonium and phosphonium polyalkylene oxide salts, and ternarysulfonium polyalkylene oxide salts and and wherein n isa positive integer at least as greatas 4 representing the least number of alkylene oxide units present in the polyalkylene oxide radical of the salt.

The quaternary and ternary polyethylene oxide salts are particularly eile'ctive as sensitizcrsfor the emulsions and have the structures V i (A) R R in,which X a'nd n are as above-mentioned and Q represents the non-metallic atoms necessary to complete an organic heterocyclic nucleus such as pyridyl, a-picolyl and "y-picolyl.

in which R it, Q and X are asabove. l

Representative cationic quaternized and ternarized 'polyalkylene-oxide salts having these formulas are:'-=f-' 1 i 010,-. I ClOr V Tetraethoxyethyl-bls-pyrldlnlum perchlorate- Nfomomoiwomom-is i e t-GaHn-Q-oomcmon-onzom-rf I I 'r -S'0 CHg I p t OetYIphenoxypolyethoxyethylpyridinium methane sulfonate (a derivative of an ethylene oxide and p-tert.-octy1- phenol in which n has an average value of 4.)

' v 010 C104- Octaethoxyethyl-bis-dimethyldodeylammonium perchlorate v1 wanes-(Ounnwn-omoHr s 0H3)1 Tetraethoxyethyl-bis-dimethylsulfonium perchlorate p t-0etylphenoxypolyethoxyethyldimethylsulfonium-p-toluene 4 sulfonate (in which 'n, has an average value of 4 Clot C104 Polyethoxyethyl-bis-pyridinium perchlorate (in which the polyethyleneoxy chain is derived from a polyethylene glycol having a molecular weight of about 300). I The quaternized polyalkylene oxide monoethers having formulas B and E above are prepared by reaction of the appropriate polyalkylene oxide monoethers such as o Pusan-O 0(omcmonomomon orniethoxypolyethylene oxide, with 'alkylsulfonyl halides such as methanesulfonyl chloride, ethanesulfonyl chloride, p-toluenesulfonyl chloride, followed by quaternization with tertiary bases as pyridine, picolines and trialkylamines such as trimethylamine, dimethylbenzylamine, dimethyllaurylamine, etc. The resulting quaternary salts s may 'be converted to salts of other anions such 'as the perchlorate in order to facilitate purification.

, The bis-quaternary compounds of formulas A and D above are prepared by reaction of polyalkylene oxides of varying molecular weight, with'the just above sulfonyl halides, followed by quaterni'zation as described just above. Thus, 'polyalkylene oxides such as polyethylene oxides having average molecular weightsof the order of about 200 to 1500 or more can be employed to provide the polyalkylene oxide radical of the sensitizers. I The cationic quaternary and ternary polyalkylene oxide sensitizers can be used in the emulsion'with'useful results in concentrations of the order of from about 0.1 gram to 6.0 grams per mole of silver halide present in the emulsion.

The syntheses of the following cationic materials also useful in the emulsions are described in the co-filed invention of Carroll, Sagal and Beavers US. patent application Serial No. 627,135.

3,6,9,12,15,18,21;24 octoxahexacosane 1,26 bis(pyr- 70 idinium methanesulfonate) 3,6,9,l2,'15,l8,21,24 octoxahexacosane 1,26 bis(pyridinium perchlorate) 3,6,9,12,15,18,21,24 octoxahexacosane 1,26 bis( trimethylammonium perchlorate) (Compound IV) 15 as so,

Polypropoxypropyl-a-w-bis (pyridinium methanesulfon'ate)-containing about 16 isopropoxy units Polypropoxypropyl-u-w-bis (pyridinium methanesulfo nate)-containing about 6 isopropoxy units The anionic polyalkylene oxide sensitizers are of various types including, e.g., the polyalkylene oxide carboglutamic 'acid salts, N-carboxymethyl carbamate salts and polyalkylene oxide sulfuric acids. These anionic materials are characterized by containing at least 4 and preferably at least 13 bivalent polyalkylene oxide radicals, such as polyethylene oxide, polypropylene oxide and polybutylene oxide radicals, to which is attached at least one anionic group. The following are representative anionicp'olyalkylene "oxide se'nsitizers useful in our invention.

(IX) 0 I 0 7 w '-0 i-omN'nii0 omomomon,omo-iiNHomii 0- New Polyeth'oxyethyl-bis-N-earboxymethylcarhamate (dlNa salt) ;or NHCOCHflOCHzOHfln-O (IN-CH1 on o 0 -Cs n slum (XI) Ns oooomwnooo(cmomomomomo-ooNHCmooo-Nv Polyethoxyethyl-bis-N-carboxymethyl carbamate (dlNa salt) H+-o,s-o cm0n,o ncnzonzo-sorm Polyethoxyethyl-bis-sulfuricacid. n: 3501 7 5 or 8 (XIII) V Na+'-o0o'oHNHooowmoniomomomo-ooNnonooo-iva Na o0 more 011, ,00 0- 1w Polyethoxyethyhbis-carboglutamic acid (Na salt) (XIV) mHnsO (0H2CHfl0)12CHaCH10-C ONHCH-C O O- Na+ (CH2)2COO" Na+ N-carbolauroxypolyethoxyethylglutamic acid (diNa salt) Na+ "SIC: s or Na+ ooo(omcmomomcmo-co SO3- Na 7 Polyethoxyethyl-bis(3,6-disulfobenzoate) (tetra Na salt) a (CHz)2QOO- Na+ "N=carb'octyloxypolyethoxyethylglutamic acid, (diNa salt) xvnr -fl-CaHi1 O(CHzCHzOhdCHaCHgO-CONHCH-COO" Na ombrnooo- Na, N-carho p o'ctylphenoxypolyethoxyethylglutamic acid (Na salt) 'p tert Octylphenoxyp'olyethoxyethylsulfate :(Nasalt) tion chilled to C. With rapid stirring, 59.0 g. (0.50 mole) of thionyl chloride was slowly added maintaining "the temperature at 0-10". During the addition a thick slurry formed. The slurry was allowed to standovernight at room temperature, poured into 400 ml. of ice water, andthe product extracted three times with 250 ml. portions of benzene. The extracts were dried over sodium sulfate, and the solvent removed leaving 65.0 g. of a dark yellow oil. The oil was fractionated,'the desired portion being collected at 237,243/0.l0.2 mm. and weighing 26.0 .g.*(23 percent yield). @Analysisr-Calc. for Ci H O Cl Cl, 16.0. Found:

-Cl,-1,6. 0.' t

. Ninei grams (0.02 mole) of nonaethylene 'glycol-di chloride was dissolved in 175 ml.of ethanol, and this solu? tion 'was added to 4.9 g. (0.04 mole) of sodium sulfite in with a solution of silver nitrate.

COMPOUND XII 7.:35 Polyethylene .oxide molecular weight 1540, 144 g.

(0.093 mole) was dissolved in 400 ml. of dichloromethane. The clear solution was cooled to 0 C., and a steady stream of nitrogen bubbled through a sintered glass tip under the surface of the liquidwhile 21.6 g. (0.185 mole) of chlorosulfonic acid was slowly added. The solution was maintained at 0 for 2 hours while the rapid stream of nitrogen drove out the hydrogen chloride formed in the reaction. The solution was allowed to stand overnight, and the dichloromethane removed under vacuum to 45".

Upon cooling, 156 g. (97 percent) of an amber liquid 5100 ml. of water. The mixture was refluxed for eighteen .hours with vigorous stirring. The aqueous ethanol was solidified to a Waxy cream solid. The bisulfuric acid I darkened slowly upon standing and rapidly upon heating.

An aqueous solution of the bisulfuric acid showed no presence of chloride ion with a silver nitrate solution.

COMPOUND XI'L (n= 75) i To 200 ml; of dichloromethane, 33.5 (0.01 mole) of 2.33 g. (0.02 mole) of chlorosulfonic acid was added.

with stirring. After two hours at 0 in the nitrogen stream, the solution was allowed to warm up to room temperature and the dichloromethane removed under vacuum to 45 C. The product was a light amber oil COMPOUND Xrx One hunderd and four grams (0.14 mole) of was dissolved in 400 ml. of dichloromethane and the solu tioncooled to 0. Then 16.0 g. (0.14 mole) of chloro- .sulfonic acid was added, with a rapid stream .of nitrogen bubbled through the solution which removed the hydrogen chloride formed. The solution was stirred at 10 for three hours in the stream of nitrogen. The dichloromethone was removed under vacuum at 40, leaving 115.0 g. of a brown, viscous syrup (99 percent yield).

weighing 31.0 g. (88.5 percent) which solidified to a. white wax upon cooling.

"6 COMPOUND 111 A mixture of 137 g. of polyethylene oxide molecular weight 1540 and 36 g. of dimethyl isocyanatoglutarate was heated at 70 :5 for twenty-four hours. During the heating the mixture was protected from atmospheric moisture. The product was transferred toa' beaker and selectively hydrolyzed by treatment with four molar equivalents (14.5 g.) of sodium hydroxide in 35. ml. of Water, The alkaline solution was added in portions with stirring, While the temperature was maintained at 60-70". The mixture was then heated for 3 hours at 60-70, water being added occasionally so as to maintain the material in a fluid state. It was diluted with water to givea' 48 percent solution which was filtered.

. COMPOUND x1- The product resulting from heating g. of polyethylene oxide molecular weight 4000 with 6 g. of ethyl isocyanatoacetate, for,4 hours on the steam bath while protected from atmospheric moisture was treated with 1.6 .g. of sodium hydroxide dissolved in about 5 ml. of water. Heating was continued on the steam bath for two hours, during which time additional amounts of water were added to maintain the product in a fluid state. Water was added to give a total weight of 150 gr Such a solution contains an estimated g. (57 percent) of solids.

a 4 COMPOUNDXVI The product obtained by heating together .87 g. of the oleyl ether of polyethylene glycol molecular weight 525 and 22 g. of dimethyl isocyanatoglutarate at= 60-70 for .20 hours in the absence of atmospheric moisture was treated with 9 g. of sodium hydroxide in 25 m1. ofwater. The mixture was heated for two hours at 60-70, water being added in small quantities to maintain the mixture in .a fluid state. It was finally diluted with Water to yield a 42 percent aqueous solution (111 gfof solid in a total weight of 262 g.) of a product that is essentially QmHasO(CH2CHZO) CONHCHGOONS CHrCHzOOONa. I in which n has the average value of COMPOUNDS Xvn and XvIn In a similar manner the cetyl ether of polyethylene glycol and dimethyl isocyanatoglutarate gave N-carbocetyloxypolyethoxy-ethyl-glutamic acid (sodium salt), and the p-tert.-octylphenyl ether of polyethylene glycol and dimethyl isocyanatoglutarate gave N-carbo-p-tert.-octylphenoxypolyethoxyglutamic acid (sodium salt). In the former casethe molecule contained an average Of' 27 CH CH O units; in the latter an average of 30 units.

COMPOUND X The amine was dissolved in absolute acetone and one equivalent of the acid chloride CH COO(C H O) CH COCI was added to the solution at room temperature. After stirring 10 min. one equivalent of quinoline was added and the reaction mixture was refluxed with stirring for 1.5 hours.

The reaction mixture was cooled, the quinolinehydrochloride precipitate was filtered out and the acetone removed under reduced pressure. The residue was crystallized from 6040 henzene -ligroin (B.P. IOU- C.).

( The product white needles, had an y. 15519550 p.

Cale. for Found, rozHmClzNzOm percent percent COMPOUND II To a solution of 42.6 g. (0.1 mole) of p-tert.-octyl- 'phe'noxytetraethoxyethanol and 11 g. (0.109 mole) of 'triethylamine (anhydrous) in dry ethyl ether chilled to 0 C. is added, in portions, 11.5 g. (0.1 mole) of methanes'ulfo'nyl chloride. The mixture is shaken thoroughly and allowed to stand at room temperature for 3 days. The trie'thylamine hydrochloride that separates is removed by filtration. Removal of the ether leaves 50 g. of a clear,-color'less liquid.

A mixture of 5.03g. (0.01 mole) of the above liquid and 0.8 g. (0.01 mole) of pyridine is heated on the steam bath for 18 hours The resulting liquid which is quite 'soluble in water is essentially p-tert.-octylphenoxytetraethoxyethylpyr'i'dinium methane sulfonate.

Compounds which are most efficaciousfor use in the emulsions together with the ionic polyalkylene oxide comarmor-q The melting point is 285-287".

pounds for reducing fog to normal levels are the azajinde'ncs, for example, a 4-hydroxy-6-alkyl-1,3,3a,7-tetra- 'z'ai'n'dene specifically 4hydro'xy6-methyl-1,3,3a,7-tetraza- "inden'e as well as 5-car'boxy-4-hydroxy-l,3,3a,7-tetrazaindene, (Reynolds U.S. Application Serial No. 520,120, filed July 5, 195-5), 1,Z bis('4-hydroxy-6-methyl-1,3,3a,7- tetrazaindene 5-yl)ethane, 1,2,3,4-tetrakis(4-hydroxy-6- met-hyl-1,3,3a,7-tetrazaindene-2-yl)butane, Z-amino-S-carboxy-4-hydroxy-1,3,3a,7-tetrazaindene, 4-hydroxy-2-B-hydroxyethyl-6-methyl-1,3,3a,7-tetrazaindene, S-carbethoxy- 4-hydroxy-1,3,3a,7-tetrazaindene, (Reynolds invention above), 7-hydrox'y1,2,3,4,6-pcntazaindene, 2,4-dihydroxy- 6-methyl-1,3a,7 triazaindene. 4-hydroxy -2'y-'hydroxyprop'y'l-6-me'thyl 1,3,3a,7-tetrazaindene and 4-hydroxy-2(4- p yridy'l)-6-methyl-1,3,3a,7-tetrazaindene.

Other azaindene compounds useful for this purpose are disclosed in the examples hereinafter, in U.S. Patents 2,716,062, 2,713,541 and V U.S. Patent 2,735,7 9, Allen et al., issued February 21,

U.S. Patent 2,743,181, Allen et al., issued April 24, 1956, U.S. application S.N. 515,785, Tinker et al., filed June 15,

U.S. Patent 2,756,147 Reynolds, issued July 24, 1956,

U.S. Patent 2,743,180, Carroll et al., issued April 24,

Zeitschrift fur Wiss. Phot. 47-, 2-28 (1952).

water and 10.4 kg. '(98 moles) anhydrous sodium carbonate was added slowly. The run was heated for three hours at 90-100 and was then'concentrated'under vacuuntil no'more water distills over (about 4-'-5 'hr.) The residue was a mushy, white solid which was cooled overnight under vacuum. Then, 144 kg. glacial acetic acid and 150 kg. (1150 moles) ethylacetoacetate were added and the mixture is refluxed for three hours. The run was cooled to room temperature and dropped into a l5g0-gal. stainless steel tank. The liquors were removed by filtration and saved for recovery. The solid was slurried in 30 gal. alcohol, filtered and centrifuged. Washing with fresh portions of alcohol was repeated until no additional color is removed and the od'orof acetic acid was-at a minimum. The white to pale pink needles were dried on paper trays in a'war-m air oven. The yie1d-was'98 kg. This is 81.5% of the theoretical quantitykg.

7-hydroxy-1-,2,3,4,6-pentazainderze I "and then from water to give 30 g. (99%) of the product. j

Found: C=35.0; H='2.7. v V 2,4-dihydroxy-6-methyt-1,3a,7-triazdirtdene To a solution of 18.4 g. (0.8 moles) of sodium in 500 ml. of dry methanol was added 23.4 g. (0.2 moles) of guanidoacetic acid followed by 52 g. (0.4 moles) of ethyl 'acetoacetate. The mixture was refluxed for 20 hours, concentrated, washed'with ether, and taken up in 5 percent hydrochloric acid until the solution 'had 'a pH 1 (about 600 ml. of acid). The insoluble material was collected and recrystallized from water to give 5g. of product melting at 310 C.

1,2-bis-4-hydroxy-6 methyl-1 ,3,3a,7-tetrazaindene-5=yl ethane N=34.4. Found: C=5-1.5, H=4.7, N=34.5.

'2-amine 5-carb0xy-4-hydr0xy-1,3,3a,7-tetrazainderte ',A mixture of guanazole (25g) and diethyl ,et-hoxymethylene malonate (5 6 g.) in ml. of .acetic 'acid was refluxed 4 hours, cooled and the 2-amino-5-carbethoxy-4-hydroxy-1,3,3a,7-tetrazaindene collected on -a Biichner funnel and-dried (46.5 g.,'83

The-es't'er (25 g.) and 250 ml. of 1 N hydrochloric acid were refluxed 4 hours, cooled, and the solid collected and recrystallized from-water to give 9 g. of the acid (M.P. above 300 (3.).

Analysis."Calcd. for C H N O C=37, H= 2.5, N=35.9. Found: C=37.9, H=2.8, N=35.6.

liter of water was refluxed 18 "hours. Precipitation begins after about 15 hours, continued refluxing for ,24

hours longer (total 42 hours). "Co'o'led to 25, filters I 9 212 grains, 57%, M.P. 223-2262 from water raises the M.P. to 233-234".

4-hydroxy-2'B-hydroxyethyl-6-methyl-1,3,3a,7- tezrazaindene Sixty-three grams of hydrazide was refluxed 20 hours in 500 ml of glacial acetic acid and 50 ml. of concentrated hydrochloric acid. The hot solution was filtered, then cooled, yielding 12 grams of white solid, M.P. 257- 2 60"; A second recrystallization from water yielded 65 grams of pure anhydrous material, M.P. 262- 263.

Recrystallization Analysisr calcdx C, 49.4; H, 5.2; N, 28.9 (C H N O 194). Found: C, 49.7; H, 4.9; N, 27.2.

1,2,3,4-tetrakis(4-hydr0xy-6-methyl-1,3,3a,7-tetrazaindene-Z-yl) butane :One hundred ninety-five grams of l,2,3,4-tetrakis(carbohydr-azido)butane (formed by reacting 1,2,3,4-t'etracarbomethoxybutane with hydrazine), 340 grams of 2-ethylmercapto-4-hydroxy-6-methylpyrimidine, 100 ml. of glacial acetic acid and 5 liters of water refluxed 24 hours, cooled well, and filtered. 1

This crude l,2,3,4-tetrakis(4-hydroxy-6-methyl-2-pyrimidylhydrazino)butane was refluxed with lliter of glacial acetic acid, and 50 ml. of concentrated hydrochloric acid for 24 hours, cooled to 0f, and filtered. The solid, recrystallized from water, yielded 39 grams of 6- methyluracil, M.P. 3103l5 (infrared spectrum, 6143A identical with that of an authentic sample, 6096A). The combined mother liquors evaporated and recrystallized from water, eventually yielded 18 grams of whitesolid, M.P. 263-265; the infrared spectrum of which is different from that of 6-methyluracil and of 2,6-dimethyl-4- hydroxy-l,3,3a,7-tetnazaindene. The analytical figures agree fairly well with the tetrahydrate, but suggest slightly incomplete conversion of carboxyl to tetrazaindene moieties.

Analysis.-Calcd: C, 46.5; H, 4.7; N, 31.0'

Found: C, 48.9; H, 5.0; N. 27.5.

The preparation of silver halide emulsions involves three separate operations: 1) the emulsification and digestion or ripening of the silver halide, (2) the freeing of the emulsion from aqueous solublesalts usually by washing, (3) the second digestion or after-ripening to obtain increased sensitivity (Mees, The Theory of the Photographic Process, 1942, page 3). The sensitizing agents may be added at any stage, preferably after the iin-al digestion.

The photographic emulsions which we use are of the developing-out type and best results have been obtained gelatino-silver bromoiodide emulsions. However, emulsions of varying silver halide content may be used.

.The emulsions may be chemically sensitized by any I of the accepted procedures, in addition to sensitizing with the ionic polyalkylene oxide compounds. The emulsions may be digested with naturally active gelatin, or sulfur compounds may be added such as those described in Sheppard US. Patents 1,574,944 and 1,623,499, .and

Sheppard and Brigham U.S. Patent 2,410,689.

The emulsions may also be treated with salts of the noble metals such as ruthenium, rhodium, palladium,

iridium and platinum, all of which belong to group VIII of the periodic table of elements and have an atomic Theemulsions may also be 'chemicallysensitized with 10 gold salts as described in Waller and DQddUzS. Patent 2,399,083 or stabilized with gold salts as described, -in Damschroder U.S. Patent 2,597,856 and Yutzy andLeermakers U.S. Patent 2,597,915. Suitable compounds are potassium chloroaurite, potassium aurithiocyanate, potassium chloroaurate, auric trichloride and 2-aurosulfobenzothiazole methochloride. e I j v The emulsions may'also be chemically sensitized with reducing agents such as stannous salts (Carroll U.S. Patent 2,487,850), polyamines such as diethylene triamine (Lowe and Jones U.S. Patent 2,518,698), polyamines such as spermine (Lowe and Allen U.S. Patent 2,521,925), or ibis-(B-aminoethyl) sulfide and its water-soluble salts (Loweand Jones US. Patent 2,521,926). j

As mentioned, when using the ionic polyalkylenefoxide derivatives for sensitizing the emulsions, any undesirable fogcan be suppressed and reduced to normal levels by using various compounds such as the .mercury compounds of Allen, Byers and Murray US. Patent 2,728,663, Carroll and Murray U.S. Patent 2,728,664, and Leubner and Murray U.S. Patent 2,728,665 granted December 27, 1955, and the organic mercury compounds of the parent invention of which this application is a continuation-inpart.

containing the polyalkylene oxide salts such as cadmium chloride; cadmium 'nitrate, cobalt nitrate, manganese chloride, managanese sulfate, zinc chloride, zinc nitrate and zinc sulfate.

The chemical sensitizingeagents and other addenda adapted particularly for use in color photography, they will ordinarily comprise the emulsion layers of multilayer 'color films which emulsion layers are customarily differentially sensitized to the primary regions of the visible spectrum and contain coupler compounds producing dye images of colors complementary to the sensitivity of the emulsion layers. In a representative color film, one or .more of the differentially sensitized emulsion layers may be sensitized with the ionic polyalkylene oxide salts, and in a typical example emulsions sensitized to the red, green and blue regions of the spectrum are superimposed on thesupport in that order and contain cyan, magenta and yellow color-forming coupler compounds respectively. A yellow filter-layer such as yellow colloidal silver is advantiageously interposed between the blue and greensensitive emulsion layers.

Since:the emulsion.layers sensitized 'with the ionic polyalkylene oxide salts of the invention contain coupler compounds they can be readily processed by well known methods to yield color negatives directly or positive images by' means of well known reversal processes. That is, after initial exposure of the emulsion to a subject a developer of the p-phenylenediamine type will produce a colored image negative in respect to the subject. Likewise, if development of the emulsion layer is first carried out with a non-co1or-forming developer followed by re- .versal exposure of the residual silver halide and then ,color development, a colored positive is obtained.

iThe coupler compounds used in the emulsion layers sensitized with the ionic polyalkylene oxide derivatives,

are any of the well known compounds wln'ch combine with the oxidation product of primary aromatic amino .silver halide colordevelopingagents to form dyes, for 6Xample,: the phenolic couplers of US, Patents 2,266,452, 2,362,598, 2,589,004, 2,474,293, 2,521,908, 2,423,730 and Other stabilizing agents may be added to the emulsions" Berke-U.S. Patent application 6,561; the pyrazolone couplers -of-U:S. Patents 1,969,479, 2,369,489, 2,600,788, 2,618,641, 2,511,231 and the open chain reactivemethylene'couplers of U.S. Patents 2,298,443, 2,652,329, 2,407,210, 2,271,238 and McCrossen et al. U.'S. Patent Application Serial No. 575,099, filed March 30, 1956.

Likewise, the emulsions may contain colored color-forming couplers as described in U.S. Patents 2,521,908, 2,706,684, 2,455,169, 2,694,703, 2,455,170 and 2,453,661. The couplers may be dispersed in the emulsion layers by means of an oily couplersolvent according to the methodsof U.S. Patents 2,304,940 and 2,322,027. However, if as may be the case, the couplers contain solubilizing groups such as 'SO H groups which render the couplers soluble in alkaline solution, the oily coupler solvent may be dispensed with-and the couplers can be added to the emulsion from aqueous-solutions as their alkalimetal salts.

The following examples will serve to illustrate our invention: i

Example example illustrates a known chemical sensitizing-effect of unquaternized polyalky-lene oxides.

A negative speed gelatinoasilver bromoiodide emulsion adjusted to optimum sensitivity with a mixture of a labile sulfur compound and a soluble gold salt was divided 'in t'o'two portions. To each portion was added, at 40 C., an equal amount of an optical sensitizing dye that sensitized the emulsion in the region 50006000 A. Each POUilOIl was then treated, beforecoating on a suitable support, as indicated below. 1

' (a) -Control-no further treatment.

-(b) 1.69 g. per mole of silver halide of the oleylet-her er a polyethylene oxide of molecular weight of about 1500, was added before coating. The resulting coatings were tested sensitometrically by exposure from $3 through a green filter to studio quality light on an in tensity scale sensitometer (Eastman lb) and developed .minutes at 75 -F., with intermittent agitation in an Elon-hydroquinone developer. The [following results were obtained:

Sample Speed l Min. Density (:1) Control .06 '(b) +10 .09

1 Speed is expressed as 100 (1-log E) where "E" is the exposure in meter candle seconds required to produce in the processed film a silver density of 0.20 above minimum density.

an equal amount of an optical sensitizing dye that sensitized the emulsion in the region 5000-6000 A and equal amounts of a magenta-forming color coupler of the pyrazolone type, 1-(2,4,6-t1'ichlorophenyl)-3[3'-(2",4"- di-t-amylphenoxy-acetamido) benzamido] -5 pyrazolone, suitably dispersed in a highahoiling lyophooic solvent. Each portion was then treated before coating on a suitable support as indicated-below.

(a) Controlno further treatment. V

(b) 1.69 g./silver mole of the above oleyl ether of polyethylene oxide was added befiore coating. The resulting coatings were tested sensitometrically by exposing in the same manner the-coatings in Example 1, devel- '12 oping to a color positive using the following commercial color process carried out at 75 F.:

. Minutes (1) Negative development 10 (2) Reversal flash exposure (3) Color development 15 (4) Silver bleaching 8 (5) Fixing 3 The negative developer had the following composition:

Water, 90 F. (32 C.) liter 1.0 Sodium hexamet-aphosphate grarns 2.0 N-methyl p aminophenol sulfate do 6.0 Sodium sulfite, desiccated .do 50.0 Hydroquinone do 6.0 Sodium carbonate, monohydrated do 35.0 Potassium bromide do 2.0 Sodium .thiocyanate do 1.5 0.5% Solution (6-nitrobenzirnidazole nitrate) cc 12.0 0.1% Solution of potassium iodide cc 10.0

The color developing solution above had the following composition:

The silver bleaching solution above had the following composition:

Water, 90 F. (32 C.) liter 1.0

Potassium dichrornate "grams" 5.0 Potassium ferricyanide do 70.0 Potassium bromide do 20.0

The fixing baths above had the following composition:

Water, 80 F. (27 C.) liter 1.0 Sodium thiosulfiate gna.m-s 150.0 Sodium bisulfite do 20.0

. The following results were obtained:

Sample Speed 1 Max. Density 7 (a) Control.

1 Speed is expressedas (1-1og E) where E is the exposure in meter candle seconds required to produce after processing a total dye density of 1.0 to appropriate illumination.

In the above data of the table, it will be apparent that sample b has higher maximum density than a since the lower sensitivity of b resulted in less silver halide being developed in the negative development step.

Example 3.The improvement in emulsion speed obtained by sensitizing emulsions containing couplers with the cationic polyalkylene oxide salts according to our invention is illustrated in this example.

A negative-speed gelatino-silver brornoiodide emulsion adjusted to optimum sensitivity with a mixture of a labile sulfur compoundand a soluble gold salt was divided into three port-ions. To each pontionwas added, at 40 C., an equal amount of an optical sensitizing dye that sensitized the emulsion inv the region 5000-6000 .A and equal amounts of a magenta-forming color coupler of the pyrazolone type (Example .2) suitably .dispersedinahigh- 13 boiling-lyophobic solvent 3 Each portion was then treated,

" (a) control-aeratin treatment." Y

(b) 2 g. per mole of silver halide of polyethoxyethyh bis-pyridinium perchlorate (compound VIII above, the

carbon chain of which has a molecularweight of about 1500 ),wasadded'before coating' T g (c) 2 grams per mole of silver halide of tetraethoxyethyl-bis-pyridinium perchlorate (compound I above) was added before coating. The resulting coatings were tested sensitometri a llby exposing and processing to acolor positive in the same manner as the coatings in Example 2. The following results were obtained:

Samp'le --Speed Max.Density Oontroh 1 Speed" is determined 'm'm manner indicated in Example 2.

The increased speed of samples b and clearly show theetfctiveness of the'polyallq len oxide salt sensitizing tizing dye that sensitized the emulsion in the region 5000-.

6000 A and equal amounts \of a magenta-forming color coupler of the pyrazolonetype, suitablydispersed in a high-boiling lyophobicsolvent. ",Each portion was then e e b fore coat 9 a s ables pp t, as d a ed below.

(a) Control-mo further treatment.

(b) 2.0 g. per mole of silver halide ofcompound II] above was added before coating,

The resulting coatings were-tested sensitometrically by exposing for, through a yellow "filterf to light of studio light-(3150 K.) qnalityonan-"intensity scale sensitometer (Eastman lb), andlldevelopedfto ,afjcol'or" negative in Developer. SD-30 (descn'bedin the Journal of the-Society of MotiouPictureand Television Engineers, vol. 61, No. 6, p. 674,December 1953). The following; resultswere obtained: 1 a 1 a Sample Speed Minimum j Density I l speed" is expressed as 100 (1log- E) where E is the exposure in metr-candle-secondsrequired to produce in the processed film a magenta dye density to green light of 0.20 above minimum green light density.

In the table, the comparatively higher minimum densityiwvalue of; 0.44;r eflec ts the mentioned desirability of using an antifoggant in the emulsions sensitized with the polyalkylene oxide-salts to reduce fog. {Example 5.,A negative-speed gelatino-silver bromoa iodide emulsion digested to optimum sensitivity with a mixture-of labile sulfur compound and a soluble gold salt ivi ed to tw Por ion T each p r was added, at 40 C., an equal amount of an optical sensitiaing dye that sensitized the emulsion in the region 5000-6000 :A and equalamounts of a magenta-forming colorcoupler of the pyrazolone type (Example 2), suitably dispersed in a high-boiling lyophobic solvent. Each, portion was further treated, before coating on a suitable support, as described below:-- h

(c) Controlm further treatment. (d) 210" g.'per'tnole of silver halide of compound III above was-added. f 1 1 The reshltingcoatings. were exposed for ,6 to the before coating 'on a suitable support, as indicated below.

light emitted by'a 5.00 w. tungsten lamp in an intensity scale sensitometer, further modulated by a green filter.

The exposed coatings (5) Washed 10' in running water. (6) Processed to a color negative as described for the coatings in Example 4.

The following results were obtained:

' Sample Speed 1 Minimum Density (c) Control..... ..07 ,4 7

1 Speed determined as in Example 4. V

As inExample 4, the comparatively high minimum density value of .27 indicates the desirability of using an antifoggantin the emulsion.

Example 6. A negative-speed gelatino-silver bromoiodide emulsion was digested tooptimum sensitivity with a mixture of labile sulfur compound'and a: solublegold salt and treated with an optical sensitizingdye that sensitiled in the region of 6000-7000 A. At 40 C. there was added a cyan color-forming coupler (6-[u'-(4-'[a-(2,4-di t amylphenoxy)butyramidolphenoxy)acetamido], 2,4- dichloro-3-methylphenol), suitably dispersed in a highboiling lyophobic solvent. The emulsion was divided into' two equal parts and further treated as indicated below;

I Control-m0 further treatment before coating. n (f). .4.0:'g. per mole of silver halide of compound III above was added at 40 C. before coating. 1 The, resulting coatings were tested sensitometrically by ..exposure for through a yellow filter to light of daylight quality on an intensity scale sensitometer(Eastman Ib) and developed to a positive in the reversal color process of Example 2. The following results. were obtained}.

Sample Speed 1 Maximum Minimum f Density Density (e) r'eference..-. 2.58 (f) +22 1.90 105 1 Speed in the reversal processed coatings is expressed as (i-logE) where E is the exposure in meter candle seconds required to produce, after processing, a total dye density to appropriate illumination of 1.0.

Sample Speed Maximum Minimum Density Density (0)-; C0ntrol 2.34 5 (11).. 58 1.70 .05

1 "Speed was evaluated on the same basis as in Example 6.

Sample Speed- 7 Maximum Minimum Density Density (i) reference. 2. 20 07 +58 1. 60 07 1 Speed values determined as in Example 6.

Coatings (f). and (i) of Examples 6, 7 and 8 were incubated in. sealed, foil envelopes for seven days at 120 F."and50% R.H. After exposure and development as described in Example 6 the following results were obtained:

Sample, Speed Maximum Minimum Density Density The data in the table shows that the pronounced speed increase resulting from the use of the cationic polyalkylene oxide salt sensitizing agents is maintainedafter stor-. age at elevated temperatures and humidity. No speed values appear in the table for samples 6(9) and 60) since neither emulsion contained an antifoggant and therefore 6(1) developed fairly high fog on incubation and the speed therefore could not be ascertained. However,'samples7.(h) and 8(j) containing both the poly-. alkylene oxide salt sensitizing agent and the azaindene antifoggant had speed values of 60 and 55 units greater than the control samples 7'(g) and 8(i).

In a similar mannerother stabilizing compounds such as the mercury compounds and azaindene compounds mentioned above can be used to lower-fog of thesensi tized emulsions to normal levels.

Example 9.A negative-speed gelatino-silver bromoiodide emulsion was digested to optimum sensitivity with" a. mixture of labile sulfur compound and a soluble gold salt and treated with an optical sensitizing dye that sensitized in the region of 6000-7000 A. At 40 C. there was added the cyan color former 6-[u-(4-[a-(2.,4-di-t-amylphenoxy)butyramidoJphenoxy)acetamido] 2,4 dichloro-3-methylphenol suitably dispersed in a high boiling lyophobic solvent. The emulsion was divided into several equal parts and further treated before coating as indicated below.

(A) Control-no further treatment.-

(B) 4.0 g. per mole of silver halide of polyethoxy ethyl-yew-bis-carboglutarnic acid, disodium salt (XIII) was added at 40 C. before coating.

7 (C) 4.0 g. of (XIII) and 4.0 g. of 4-hydroxy-6- methyl-l,3,3a,7-tetrazaindene (AZA) per mole of silver halide were added at 40" C. before coating.

(D) 4.0 g. of polyethoxyethyl-' ,w-bis-N-carboxymethyl carbamate, disodium 'salt (JG) per mole of silver halide was added before coating.

(E) 4.0 g. of (XI) and 4.0 g. of (AZA) per'mole of silver halide were added before coating.

(F) 4.0 g. of polyethoxyethyl-v,w-bisulfuric acid (XII) per mole of silver halide was added before coating.

(G) 4.0 g. of (XII) and 4.0g. of (AZA) were added before coating.

The resulting coatings were tested sensitometric'ally by exposure for through a redfilter to light of daylight quality on an intensity scale sensitometer (Eastman Ib) and developed-- p I I r Process A to a silver negative in thefirst developer of the process of Example 2. Y

Process B to a reversal color positive'in the process of Example 2.

The following, results were obtained:

The coatings wereincubated in"heat-sealed" metal foil envelopes forsevendays at-120, F.'/ 50% RH. andagain testedin ProcessB. The following results were obtained.

The data show 'the efi'eetive'nms of the anionic'polyalkylene oxide sensitizers in increasing speed; and in combination with the 'azaindene compound of'maintain ing maximum density after incubation;

Exqmple10.'-A negative speed of gelatino-silver bromoiodide emulsion was adjusted to optimum sensitivity with a mixture of labile sulfur compound and a soluble gold salt. At 40 C. there'wasadded the yellow color former N -(4-benzoylacetamidobenzene s lfo y i-N-(vw phenylpropyl)-p-toluidine suitably dispersed in: a high boiling'lyophobic solvent." The meltwasdivide'dinto three equalrparts andtreated asbelow:

(a') Controlno further treatment.

(b) 1 g./'mole-'of silver halideofthe pyridinium' compound'II I was added at' 40" C. before coating.

(0) 1 g./mole of'silv er'halide compound HI and 4- g. of 4-hydroxy-6 meth yl-l;3,3a;7 azaindene' was added at 40 C. before-coating.

The resulting coatings were tested sensitometrically'in the same manner as Example 4." The follbwingre sults' were obtained:

The coatings were sealed in metal foil envelopes and in: .cubated' for 7 days;-at.120 F ./.5 0%;R.I I. These-coatings '17 were developed to a color negative in the manner described above (Example 4). The following results were obtained:

18 These coatings were also exposed and developed to a color positive in the manner describedin Example 6. The following results were obtained.

Sample Speed AMlnlmum 5 Sample Speed AMaximum Density Density (0) Control--- Control. (11).; Control.--.. Control. (b) -46 +.46. (b). .10. (e)... +44 -.01. (c) Control-.. Control.

The values of +44 and -.01 show that the speed is maintained and little fog is obtained uponincubation of the stabilized Sample c.

Example 11.--An emulsion melt was prepared as described in Example 6. The melt was divided into three equal parts and further treated as indicated below:

(a) Control--no further treatment.

(b) 4 g./mole of silver halide of compound III above was added before coating.

(c) 4 g./mole of silver halide of compound III and 4 g. per mole of silver halide of 1,2-bis-(4-hydroxy-6-methyll,3,3a,7-tetrazaindene-5-yl)-ethane was added before coating. These coatings were exposed and developed to a color positive like those in Example 6. The following These coatings were incubated for three days at 120 F] 50% RH. and processed in the same manner as the fresh coatings. The following results were obtained.

Sample Speed AMaximnm Density (a) Control. Control. ((7) 2.l0. (6)." +.32 1.0.

Example 12.-Emulsi0n melts like that in Example 6 were prepared and divided into several equal parts and further treated as indicated below:

(a) Control-No further treatment.

(b) 2 g./mole of silver halide of p-t-octylphenoxydiethoxyethyl pyridinium methane sulfonate II was added before coating.

Sample Speed AMexlmum Density Control Control. .16. (c).- -.04.

Example 14. -The anionic coupler compound X above was added to samples of a coupler-free emulsion prepared as in Example 2 in the amounts shown below. Samples were then processed to a color positive by the method of Exa'mpleZ and to a color negative by the process of Example 4 with the following resultsz Example 2 Process Example 4 Process GIILAXIMOIB A D max. Speed A Log A D min. Speed A Log a E Change EChange 2 .l6 +15 Log 0.02 +08 Log E. 4 V 20 +18 Log E 0.02 +08 Log E.

Example I5.--The ionic compounds XI and III were added to coupler-free emulsions prepared as in Example 2 and the following couplers:

Coupler I (c) Control for (d).

(d) 2 g./mole of silver halide of polypropylene glycola,w-bis-pyridinium methane sulfonate derived from polypropylene glycol molecular weight 425 was added before coating. These coatings were exposed and developed to a color negative in the manner described in Example 4 and the following results were obtained.

Sample Speed AMinimum Density Control Control. No change. (0%... Control Control. (d)- +1 +32.

1'9 with the results shownin the following table after processing in Example 1 process Example 1,6.Two, three-color reversal films were prepared as follows:

(1) On a suitable-film support were coated successively:

(a) A red and blue light-sensitive bromoiodide emulsion and a cyan-color former, (b) A gelatin interlayer, (c) A green and blue light-sensitive bromoiodide emulsion and a magenta-color former, ((1)-A Carey Lea silver-blue light filter layer (e) A blue light-sensitive bromoiodide emulsion and a yellow-color former, (f) A protective gelatin overcoat. I (2) A multilayer coating like (1) except that to layers (a), (c), and (2) were added before, coating 4 g. per mole silver halide of 4-hydroxy-6- methyl-1,3,3a-7-tetrazaindene, and 4 g. per mole silver halide-of compound XI. I e a (2) To green light the threshold log E advantage was (3) To blue light the threshold log E advantage was Example 17.A three-color reversal film was prepared similar to. film 1 of Example- 16 except layers (a) and (e) contained 3, 6, 9, 12, 15, 18, 21, 24-octoxahexacosanebis-pyridinium perchlorate, 4-hydroxy-6-methyl-l,3-,3a,7- tetrazaindene and 6-methyl-4-phenyl-mercapto-1,3,3afltetrazaindene. This film was processed as in Example 16 and the following advantages over film 1 of Example 16 which contained no ionic polyalkylene oxide compound were observed.

(1) To red light, a threshold log exposure advantage of 0.34 (log meter candle seconds).

(2) To green light the threshold log E advantage was 0.15.

(3) To blue light the threshold log E advantage was 0.34;

Emulsions chemically sensitized in the manner of the above examples and optically sensitized to the primary regions of the spectrum and further containing coupler compounds for forming subtractively colored dye images on color development may be superimposed on a support to provide multilayer color films which can be processed directly to a negative or indirectly to a color positive using the color processing procedures illustrated in the above examples.

It will be understood that we include within our invention all modifications and equivalents falling within the scope of the appended claims.

We claim:

1. A light-sensitive silver halide emulsion containing a coupler compound capable of reaction with the oxidation product of a primary aromatic amino silver halide developing agent to form a dye, said emulsion containing a sensitizing agent of the class consisting of (1) a watersoluble salt of a compound having the general formula '20 R represents ah alkylene group of from 2 m 4. carbon atoms, X and Y represent the. samerradical of the class consisting of /R1 -T-Rs -oiiNnonooon omncoon S'OZH wherein R R and R each represent alkyl groups, Q represents the non-metallic atomsnecessary to. complete. a pyridyl nucleus, X represents an acid radical, and (2) a compound having said. formula wherein X represents a member'of the class consisting of alkoxy and alkylphenoxy groups. i

2. The emulsion of claim 1 further containing a hy- 5 droxytetrazaindene stabilizing agent.

3. A light-sensitive silver halide emulsion containing (1) a coupler compound capable of reaction with the oxidation product of a primary aromatic amino silver halide developing agent to form a dye, (2.) a hydroxytetrazaindene stabilizing agent and (3) a sensitizing agent having the general formula wherein n represents a positive integer greater than 3, R represents an alkylene group of from 2 to 4 carbon atoms and R1, R and R represent alkyl groups, and X represents an acid radical.

4. A light-sensitive silver halide emulsion containing (1) a coupler compound capable of reaction with the,

oxidation product of a primary aromatic amina silver halide developing agent to form a dye (2) a hydroxytetrazaindene stabilizing agentand (3) a sensitizing agent having the general formula wherein n represents; a positiveinteger greater than, 3, R

wherein n represents a positive integer greater than. 3. 7'5 representsanalkylene groupof from 2to 4.carbon.atoms,

wherein n represents a positive integer greater than 3, Q represents the non-metallic atoms necessary to complete a pyridyl nucleus and X represents an acid radical.

7. A light-sensitive silver halide emulsion containing 1) a coupler compound capable of reaction with the oxidation product of a primary aromatic amino silver halide developing agent to form a dye, (2) a hydroxytetrazaindene stabilizing agent and (3) a water-soluble salt of a sensitizing agent having the general formula HOOCCH NHCOO(RO-) ROCONHCH COOH wherein n represents'a positive integer greater than 3.

9. A light-sensitive silver halide emulsion containing (1) a coupler compound capable of reaction with the oxidation product of a primary aromatic amino silver halide developing agent to form a dye, (2) a hydroxytetrazaindene stabilizing agent and (3) a water-soluble salt of a sensitizing agent having the general formula HOQGHNHQO0(-R0-)..R-00ONHOH000H 3000mm): HzhCOOH wherein n represents a positive integer greater than 3 and R represents an alkylene group of from 2 to 4 carbon atoms.

10. A light-sensitive silver halide-emulsion containing (1) a coupler compound capable of reaction with the oxidation product of a primary aromatic amino silver halide developing agent to forma dye, (2) a hy- +1 R0 (-R 0-),,R N e wherein R represents an alkylphenyl radical, R represents an alkylene group of from 2 to 4 carbon atoms, n represents a positive integer greater than 3, Q represents the non-metallic atoms necessary to complete a pyridyl nucleus and X represents an acid radical.

12. A light-sensitive silver halide emulsion containing (1) a coupler compound capable of reaction with the oxidation product of a primary aromatic amino silver cameo on 22 halide developing agent to form a dye, (2) a hydroxytetrazaindene stabilizing agent and -(3) a sensitizing agent having the general formula wherein R represents an alkyl phenyl radical, n represents a positive integer greater than 3, Q represents the non-metallic atoms necessary to complete a pyridyl nucleus and X represents an acid radical.

13. The emulsion of claim 3 wherein the stabilizing agent is 4hydroxy-6-methyl-1,3,3a,7-tetrazaindene.

14. A light-sensitive silver halide emulsion containing (1) a coupler compound capable of reaction with the oxidation product of a primary aromatic amino silver halide developing agent to form a dye, (2.) a hydroxytetrazaindene stabilizing agent and (3) a polyethoxyethyl-bis-pyridinium perchlorate, the polyethylene oxide radical of which contains at least 4 ethylene oxide units.

15. A light-sensitive silver halide emulsion containing (1) a coupler compound capable of reaction with the oxidation product of a primary aromatic amino silver halide developing agent to form a dye, (2) a hydroxytetrazaindene stabilizing agent and (3) octaethoxyethyl-bis-pyridinium perchlorate.

16. A light-sensitive silver halide emulsion containing (1) a coupler compound capable of reaction with the oxidation product of a primary aromatic amino silver halide developing agent to form a dye, (2) a hydroxytetrazaindene stabilizing agent and (3) tetraethoxyethylbis-pyridinium perchlorate.

17. A light-sensitive silver halide emulsion containing (1) a coupler compound capable of reaction with the oxidation product of a primary aromatic amino silver halide developing agent to form a dye, (2) a hydroxytetrazaindene stabilizing agent and (3) a water-soluble salt of polyethoxyethyl-bis-N-carboxymethyl carbamate.

18. A light-sensitive silver halide emulsion containing (1) a coupler compound capable of reaction with the oxidation product of a primary aromatic amino silver halide developing agent to form a dye, (2) a hydroxytetrazaindene stabilizing agent and (3) a water-soluble salt of polyethoxyethyl-bis-carboglutamic acid.

19. A light-sensitive silver halide emulsion containing (1) a coupler compound capable of reaction with the oxidation product of a primary aromatic amino silver halide developing agent to form a dye, (2) a hydroxytetrazaindene stabilizing agent and (3) .polyethoxyethylbis-sulfuric acid.

20. A light-sensitive silver halide emulsion containing a coupler compound capable of reaction with the oxidati-on products of a primary aromatic amino silver halide developing agent to form a dye, said emulsion being sensitized with a member of the class consisting of tetraethoxyethyl-bis-pyridinium perchlorate, p-t-octylphenoxypolyethoxyethylpyridinium methane sulfonate, octaethoxyethyl-bis-pyridinium perchlorate, octaethoxyethylbis-trimethylammonium perchlorate, octaethoxyethy-l-bisdimethyldodecylammonium perchlorate, tetraethoxyethyl his dimethylsulfonium perchlorate, p t octylphenoxypolyethoxyethyldimethylsulfonium p toluene sulfonate, polyethoxyethyl bis pyridinium perchlorate, polyethoxyethyl bis N carboxymethylcarbamate (di- Na salt), polyeth0xyethyl-bis-N-carboxymethyl carbamate (diNa salt), polyethoxyethyl-bis-sulfuric acid, polyethoxyethyl-bis-carboglutamic acid (Na salt), N-carbolauroxypolyethoxyethylglutamic acid (diNa salt), polyethoxyethylbis(3,5 disulfobenzoate) (tetra Na salt), N carbooleyloxypolyethoxyethylglutamic acid (diNa salt), N carbocetyloxypolyethoxyethylglutamic acid (diNa salt), N-carbo-p-octylphenoxypolyethoxyethylglu- 2s tamic acid (Na salt) and p-tert-octylph ethylsulfa te (N a salt) enoxyp'olyethoxy- References Cited in th fil of pat ent UNITED. STATES PATENTS 

1. A LIGHT-SENSITIVE SILVER HALIDE EMULSION CONTAINING A COUPLER COMPOUND CAPABLE OF REACTION WITH THE OXIDATION PRODUCT OF A PRIMARY AROMATIC AMINO SILVER HALIDE DEVELOPING AGENT TO FORM A DYE, SAID EMULSION CONTAINING A SENSITIZING AGENT OF THE CLASS CONSISTING OF (1) A WATERSOLUBLE SALT OF A COMPOUND HAVING THE GENERAL FORMULA 